Two separate shooting incidents in the United States left at least 10 people dead and scores injured on Monday night, police said.

One shooting occurred in a mall in Salt Lake City, Utah, while the second occurred in an office building in Philadelphia.

A Salt Lake City Police officer is on the scene next to a body inside the Trolley Square Mall, Monday night.
(Deseret Morning News/Mike Terry/ Associated Press)

The Utah shooting occurred at about 6:45 p.m. MT, local police said, when a man armed with a shotgun entered the Trolley Square Mall and began shooting people at random, killing five people and injuring several others.

The rampage ended when the man was killed, police said. An off-duty officer from Ogden was in the mall and involved in the final exchange, said Ogden police Sgt. Blaine Clifford, who declined to release the officer's name.

A witness reported seeing the gunman, who was backed into a children's clothing store, exchanging gunfire with a police officer then going down.

"We have six fatalities and multiple victims at hospital," Det. Robin Snyder said. "They were found throughout the mall."

For hours after the shooting, police were searching through stores for shoppers and employees who were hiding from the gunman.

Barb McKeown, 60, was in an antique store when two frantic women ran in and said a gun was being fired.

"Then we heard shot after shot after shot," McKeown said.

Gunman opens fire at business meeting

In Philadelphia, police said a man fatally shot three men at a business meeting before exchanging fire with police and committing suicide.

Another man was critically wounded, while two other men, who had been bound with duct tape, were less seriously injured, police said.

Police, who were called to the scene at about 8:30 p.m. ET, said the gunman appeared to get upset at the board meeting of a marketing or investment company.

Police did not know the name of the company, but said the shootings occurred in a conference room at the Philadelphia Naval Business Center.

Police did not release any other details late Monday.

"This is a tragic situation, one you never hope will hit Philadelphia," said Deputy Commissioner Richard Ross.

With files from the Associated Press